// $Id: StreamByteSource.java,v 1.5 2010-06-29 22:07:41 scipio Exp $

/*									tab:4
 * Copyright (c) 2000-2003 The Regents of the University  of California.  
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the
 *   distribution.
 * - Neither the name of the University of California nor the names of
 *   its contributors may be used to endorse or promote products derived
 *   from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
 * THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Copyright (c) 2002-2003 Intel Corporation
 * All rights reserved.
 *
 * This file is distributed under the terms in the attached INTEL-LICENSE     
 * file. If you do not find these files, copies can be found by writing to
 * Intel Research Berkeley, 2150 Shattuck Avenue, Suite 1300, Berkeley, CA, 
 * 94704.  Attention:  Intel License Inquiry.
 */


package net.tinyos.packet;

import java.io.*;

abstract public class StreamByteSource implements ByteSource
{
    protected InputStream is;
    protected OutputStream os;
    protected boolean opened;

    protected StreamByteSource() {
    }

    abstract protected void openStreams() throws IOException;
    abstract protected void closeStreams() throws IOException;

    public void open() throws IOException {
	openStreams();
	opened = true;
    }

    public void close() {
	if (opened) {
	    opened = false;
	    try { 
		os.close(); 
		is.close();
		closeStreams();
	    }
	    catch (Exception e) { }
	}
    }

    public byte readByte() throws IOException {
	int serialByte;

	if (!opened)
	    throw new IOException("not open");

	try {
	    serialByte = is.read();
	}
	catch (IOException e) {
	    serialByte = -1;
	}

	if (serialByte == -1) {
	    close();
	    throw new IOException("read error");
	}

	return (byte)serialByte;
    }

    public void writeBytes(byte[] bytes) throws IOException {
	if (!opened)
	    throw new IOException("not open");

	try {
	    os.write(bytes);
	    os.flush();
	}
	catch (IOException e) {
	    close();
	    throw new IOException("write error");
	}
    }
}
